I've never hit or ran over a dog but I would stop if it ever happens. Its just the right thing to do in most cases. No need for any animal to suffer if it cant be saved.
You really cant hold it against some folks that just leave though. I have seen it before when the drivers were terribly shaken and just not thinking assuming that the animal was dead.
From what I have seen, men usually stop and women freak out and keep driving.

i ain't touching that one brother...
